1. Field of the Invention
The present invention relates to a tube connecting apparatus for melting to cut flexible tubes and for connecting the tubes by mutually contacting the cut end faces.
2. Description of the Related Art
A tube connecting apparatus is used, for instance, for providing a dialysis solution into an abdominal cavity of a patient who requires Continuous Ambulatory Peritoneal Dialysis (CAPD) by providing connection between a transfer tube connected with the abdominal cavity and a tube connected with a dialysis pack.
An example for connecting operations of a tube connecting apparatus will be briefly explained below. As exemplarily shown in FIG. 18, two tubes 7,8 are grasped at two portions, that is, between a fixed clamp 311 and a movable clamp 312 of a first tube holder 301 and between a fixed clamp 313 and a movable clamp 314 of a second tube holder 302. The movable clamps 312, 314 are moved into contact with, and away from, the fixed clamps 311, 313. The tubes 7,8 grasped by the first tube holder 301 and the second tube holder 302 are squeezed flat in cross section, closing the interior of the tubes.
Then, a heated cutting plate (hereinafter referred to as xe2x80x9cwaferxe2x80x9d) 6 is moved upwards between the first tube holder 301 and the second tube holder 302, thereby melting to vertically cut the tubes 7,8.
In the first tube holder 301 is provided a pair of semicircular rotor pieces 303, 304 which are made into contact with each other to constitute a clamp rotor 305.
After the cutting of the tubes 7, 8, the rotation of the clamp rotor 305 grasping the cut tubes (7a, 8a) of one side of the tubes (7, 8), as shown in FIG. 19, inverts the cut tubes 7a, 8a while allowing their cut end faces to slide along a side surface of the wafer 6.
Upon completion of inversion of the cut tubes 7a,8a, the wafer 6 is retracted when the cut end faces of mutually different tubes (7a and 8b, 8a and 7b) are positioned coaxially, facing each other, and the cut end faces of the different tubes are pressed to each other to be welded. Thus, two tubes 9, 10 are formed as illustrated in FIG. 20.
The above described tube connecting apparatus is arranged such that inversion of the cut tubes is performed by the clamp rotor 305 structured of the pair of rotor pieces 303, 304. FIG. 21 is a sectional view of the clamp rotor 305 mounted in the first tube holder 301.
The clamp rotor 305 is constructed of the pair of semicircular rotor pieces 303, 304 with teeth formed on the periphery thereof, and is so constituted as to make one gear when the rotor pieces 303,304 come in contact with each other. At a center of the clamp rotor 305, that is, at the center of the contact surfaces of the rotor pieces 303, 304, U-shaped grooves 331, 332 are formed deep enough to allow the insertion of one tube, and closing portions 333, 334 are provided forming shallow grooves to squeeze and grasp the tubes.
Such the rotor pieces 303, 304 are respectively mounted in rotor mounting portions 323, 324 formed in blocks 321, 322 constituting the fixed clamp 311 and the movable clamp 312.
On the other hand, a drive gear 306 which is in mesh with the rotor piece 303(304) is rotatably mounted in a gear mounting portion 325 formed continuously to the rotor mounting portion 323. The drive gear 306 is further connected to a motor shaft of a driving motor (not illustrated).
When the tubes 7, 8 are grasped and then cut as shown in FIG. 18, the unillustrated driving motor is driven at a specified timing such that rotation is transmitted to the driving gear 306. In this manner, the clamp rotor 305 is rotated within the first tube holder 301 and the rotor pieces 303, 304 is turned to change places of cut tubes 7a, 8a. 
However, the conventional tube connecting apparatus mentioned above has the following disadvantages.
(1) The first and second holders 301, 302 need to be moved closer to each other for securing operations of pressing the cut end faces of the tubes to each other after retracting the wafer 6. Therefore, for clamping the tubes 7, 8 by the first tube holder 301 and the second tube holder 302, the movable clamp 312 is fixed to the fixed clamp 311 and, separately therefrom, the movable clamp 314 is fixed to the fixed clamp 313. In this way, in order to fix the movable clamps 312, 314 to the fixed clamps 311, 313, similar works need to be repeated, regardless of manually or automatically, thereby causing useless redundancy in view of operation as well as structural arrangement.
(2) The conventional tube connecting apparatus employing the clamp rotor 305 is arranged such that the rotor pieces 303, 304 are exposed to the exterior when the blocks 321, 322 are separated. In case the user presses the rotor pieces 303, 304, therefore, the rotor pieces 303, 304 will be displaced from each position after tube connection where the tubes are held symmetrically with respect to each other.
Thus, in case the rotor pieces 303, 304 should be made contact with each other as being still displaced, either one will be pushed by the other to be slightly rotated. Thus the clamp rotor 305 will be misaligned relative to a reference condition in which the rotor pieces 303, 304 are accurately mounted in symmetric relation to each other in the blocks 321, 322 as shown in FIG. 21. Accordingly, if the apparatus is actuated in this condition with the tubes 7, 8 being not clamped symmetrically, misalignment of the cut end faces of the tubes 7, 8 is caused by inversion of the clamp rotor 305, which may result in connection errors.
(3) While the tubes 7, 8 are clamped by the first and second tube holders 301, 302, if the movable clamps 312, 314 are erroneously separated from the fixed clamps 311, 313 before the tubes 9, 10 are alternately joined to each other, the tubes 7, 8 will be released from the first and second holders 301, 302. As a result, the alternate joining of the tubes 9, 10 can not be ensured. It is therefore necessary to prevent the fixed clamps 311, 313 from being separated from the movable clamps 312, 314 before completion of alternate connection of the tubes. However, the conventional apparatus is provided with no functions for reliable such the prevention.
The present invention has been made in view of the above circumstances and has an object to overcome the above problems and to provide a tube connecting apparatus capable of reliably perform connection of tubes.
Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the purpose of the invention, there is provided a tube connecting apparatus including: a first tube holder provided with a pair of holding members for holding a plurality of flexible tubes; a second tube holder provided with a pair of holding members for holding the plurality of flexible tubes; cutting and connecting means for heating and melting the plurality of flexible tubes held in the first tube holder and the second tube holder to cut the tubes by a heated cutting plate which is moved between the first tube holder and the second tube holder and to connect the tubes cut by the cutting plate by contacting cut end faces of the cut tubes held in the first tube holder with those of the cut tubes held in the second tube holder, the cut tubes to be connected being parts of originally different tubes; and joining members for integrally connecting one of the pair of holding members of the first tube holder to one of the pair of holding members of the second tube holder, the joining members being arranged so that one of the tube holders is movable with respect to the other tube holder.
In the above tube connecting apparatus of the invention, the joining members integrally connect one of the pair of holding members of the first tube holder to one of the pair of holding members of the second tube holder so that the first tube holder may be moved with respect to the second tube holder. This makes it possible to ensure movements of the tube holders to press the cut end faces of the different tubes to be connected. Furthermore, ones of the holding members which are connected by the joining member can be moved integrally without the need for individual manipulation of the connected holding members, thereby improving operability of the holding members.
In the above tube connecting apparatus, preferably, the joining members are of buckle configurations, specifically, the joining members include a first buckle member and a second buckle member movably attached to the first buckle member, and the first and second buckle members are provided integrally in the holding members each being one of the pair of holding members of the first and second tube holders.
According to such the tube connecting apparatus, the first and second buckles provided integrally in ones of the holding members. Even if the holding members of the first and second tube holders are integrally connected by the joining members to each other, the joining members including the buckles provided in the holding members enables movements of the tube holders to press the cut end faces of the different tubes to be connect. Furthermore, ones of the holding members which are connected by the joining member with the first and second buckles can be moved integrally without the need for individual manipulation of the connected holding members, thereby improving operability of the holding members.
It is further preferable that the above tube connecting apparatus includes release preventing means for preventing, under predetermined conditions, release of the tubes from the first tube holder and the second tube holder after the plurality of flexible tubes are held in the first tube holder and the second tube holder.
Preferably, the predetermined conditions include a period required until completion of connection of the tubes.
Preferably, the release preventing means includes a solenoid and an engaging member, and release of the tubes held from the first tube holder and the second tube holder is prevented by the engaging member that moves in accordance with excitation and demagnetization of the solenoid.
According to the above tube connecting apparatus, after the first and second tube holders hold therein the tubes, under the predetermined conditions, the release preventing means prevents release of the tubes from the first and second tube holders. Specifically, in association with the excitation and demagnetization of the solenoid, the engaging member is moved to prevent the first and second tube holders from erroneously releasing the tubes held therein until completion of connection of the tubes. Thus, the cut tubes of one side of the tubes, after mutually translocated, can be reliably connected to the other cut tubes.
According to another aspect of the present invention, there is provided a tube connecting apparatus including: a first tube holder provided with a pair of holding members for holding a plurality of flexible tubes; a second tube holder provided with a pair of holding members for holding the plurality of flexible tubes; cutting and connecting means for heating and melting the plurality of flexible tubes held in the first tube holder and the second tube holder to cut the tubes by a heated cutting plate which is moved between the first tube holder and the second tube holder and to connect the tubes cut by the cutting plate by contacting cut end faces of the cut tubes held in the first tube holder with those of the cut tubes held in the second tube holder, the cut tubes to be connected being parts of originally different tubes; and release preventing means for preventing, under predetermined conditions, release of the tubes from the first tube holder and the second tube holder after the plurality of flexible tubes are held in the first tube holder and the second tube holder.
In the above tube connecting apparatus, after the first and second tube holders hold therein the tubes, under the predetermined conditions, the release preventing means prevents release of the tubes from the first and second tube holders. Thus, the tubes can be surely held in the first and second tube holders until completion of connection of the tubes, so that the cut tubes of one side of the tubes, after mutually translocated, can be reliably connected to the other cut tubes.